<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .flex-container {
            display: flex;
            flex-direction: column;
            width: 300px;
            height: 400px;
            padding: 10px;
            background-color: #ccc;
        }
        
        .flex-item {
            width: 50px;
            height: 100px;
            margin: 5px;
            background-color: lightblue;
            text-align: center;
            color: #333;
            flex: 0 0 100px;
        }
    </style>
</head>

<body>
    <div class="flex-container">
        <div class="flex-item">1</div>
        <div class="flex-item">2</div>
        <div class="flex-item">3</div>
        <div class="flex-item">4</div>
        <div class="flex-item">5</div>

</html>